1. Field of the Invention
The present invention relates to upsetted hollow bore tubing, drill pipe, and the like having box and pin joints on opposing ends. Upsetted tubing and drill pipe are used in the drilling, production and reworking operations of oil, gas and water wells. The present invention more particularly relates to prolonging the usefulness of a section of upsetted tubing, drill pipe and the like by removing the damaged portions of the upsets having either a box and pin joint and adding an upset extension with either a box and pin joint. The upset extensions have the same outer diameter and the same inner bore diameter as the upsets of existing sections of tubing, drill pipe and the like.
2. General Background
Sections of upsetted hollow bore tubing, drill pipe and the like having box and pin joints on opposing ends are commonly used in the drilling, production and reworking of oil, gas and water wells. A section of upsetted tubing or drill pipe is generally thirty feet long. Multiple sections of tubing or drill pipe are connected together at the rotary table of a rig to form a drill, work or production string. A tubing or drill string is formed by rotatably engaging the threaded connections of the box joint on one section of tubing to the threaded connection of the pin joint of another section of tubing. After a tubing section is so connected, it is lowered into the bore hole and other sections of tubing are connected in like manner until the desired length of the tubing string is achieved.
Upsetted tubing or drill pipe may perform functions in the bore hole. In a rotary drilling operation, besides being used as a drill string, upsetted tubing may be inserted in the bore hole to test and produce the well after the hole has been drilled and casing has been set to prevent pressure from causing the hole to collapse. A string of upsetted tubing is also used to clear a bore hole that has been blocked by cement plugs, lost tools and the like. Upsetted tubing is also used after a bore hole has been drilled to place flow regulation equipment in the bore hole as well as to ream, clean and swab the hole to maintain production.
Box and pin joints on the upsets of tubing are susceptible to damage while the tubing is being transported to and from the drilling rig as well as while sections of tubing are being connected to one another in the formation of a string of tubing. Thread damage to the box or pin joints may be repaired, by cutting off the damaged area of the upset and machining new threads in the joint. However, where the damage to the upset requires removal of substantially all of the upset or where an upset has been repeatedly damaged and machined to a point where the upsetted joint is too short to be useful, the entire thirty foot section of tubing must be scrapped. Discarding an entire section of tubing or drill pipe because of a damaged or shortened upset is wasteful and costly.
Methods for protecting the joints of tubing upsets from damage and thereby prolonging their usefulness have been used commercially in the oil industry. Some drill tube connectors, wear collars and the like have been patented. Several are noted hereinafter.
U.S. Pat. No. 1,859,809 issued to E. Timbs shows a tool joint with a lock ring sub. The tool joint has a weld locking means which prevents the tool joint from backing off of its threads when exposed to high fluid pressures.
U.S. Pat. No. 1,364,478 issued to P. Boyd and A. M. Saunders shows an intermediate coupling used to join two tube sections. The coupling has a surplus shoulder length, that may be cut back and rethreaded when the original threads become damaged.
U.S. Pat. No. 2,232,135 issued to W. Pate discloses a replacement sleeve or ring which is slidable over and welded to sections of drill stems.
U.S. Pat. No. 2,298,049 issued to Robert I. Gardner shows a tool joint internally threaded at both ends to receive drill pipe at one end and a tool shank at the other end. The tool joint has a main cylindrical body of steel over which is secured a relatively thick outer wear sleeve of austentic manganese steel.
U.S. Pat. No. 2,420,139 issed to F. R. Kelly shows a coupling designed to be welded onto a pipe line in order that a section of pipe may be turned to allow for the repair of corrosion on the outside bottom of the pipe section.
U.S. Pat. No. 2,482,962 issued to Elvin G. Boice shows a wear collar or sleeve for tool joints which will remain coupled to a section of drill pipe as a drill stem is dismantled.
U.S. Pat. No. 2,626,190 issued to Elvin G. Boice discloses a tool joint of the shrink grip type having a section onto which hard metals may be welded in the field without disturbing the connection between the joint and the pipe.
U.S. Pat. No. 3,572,771 issued to Fletcher Redwine shows connectors for drill collars that are made of highly wear resistent material such as titanium or a titanium-base alloy.
U.S. Pat. No. 3,923,324 issed to James R. Cruickshank and Rainer Jurgen discloses a drill collar body having a sub with threaded connections frictionally mounted by means of a shrink fit.
The foregoing patents show some methods and apparatus for extending the life of sections of tubing. These devices however fail to disclose the method and apparatus of the present invention which in a straightforward and easy manner solves the problem of repairing sections of tubing, drill pipe or the like whose upsets have been shortened to such an extent that further rethreading is not feasible.